Method of preserving fish and similar food products of animal origin



Patented sq. 29, 1942 UNITED STATES PATE NT OFFICE Marnon or raasanvmc.FISH AND smu- LAB FOOD PRODUCTS or ANIMAL carom Rudolf Thileniu s,Frankfort-on-the-Main, Germany; vestedin the Alien Property Custodian NoDrawing. Application November 17, 1939, Se-

iigazl8 No. 305,014 In Germany November 24,

(Cl. 99195) This invention relates to a process for the Claims.

It is one of the objects of this invention to develop a process for thepreservation of fish, meats, and other foodstuffs of animal origin whichwill insure the preservation of those foodstuffs such as fish, forexample, for relatively long periods of time. It is another object ofthis invention to develop an improved process for the preservation offoodstuffs of animal origin by the action of hydrogen peroxide whereinthose food products will be preserved for a period of time considerablylonger than that period during which the preserving agent hydrogenperoxide has previously been considered to exert an effective germicidalaction. Still another object of this invention is to develop an improvedmethod for the preservation of foodstufi's of animal origin wherein thefoodstuff can be subjected to the improved preservation treatment andthen packed in ice containing hydrogen peroxide, in accordance withmethods now known to the art as described in my patent 2,150,616, issuedMarch 14, 1939. These and still further objects of this invention willbe more clearly apparent from the ensuing disclosure.

The use of ice containing hydrogen peroxide for the preservation offoodstuffs, particularly foodstuffs of animal origin, is already knownto specialists in food preservation. Ice containing hydrogen peroxidehas been found especially valuable for the storage of fish.Unfortunately, due to the inability in the past to prepare ice with asufliciently high concentration of hydrogen peroxide, the foodstufis ofanimal origin have not, in general, been preserved for the period oftime of longest duration which would be desired by those engaged in thefish preserving industry. While my issued patent discloses a process forpreparing ice containing hydrogen peroxide wherein the ice is renderedmore effec-- than that possible by the.use of the special ice containinghydrogen peroxide disclosed in my issued patent.

It has now becn found that improved preserving action is secured in thepreservation of foodstaffs of animal origin such as fish, meat or otherperishable foodstuffs, if the foodstuff is'flrst subjected to the actionof an aqueous solution of hydrogen peroxide for a relatively shortperiod of time. I'he aqueous solution of hydrogen peroxide should have apH value falling within the range 3.0 to 5.0, and the foodstuff ofanimal origin may be immersed in the solution, sprayed with the aqueoussolution of hydrogen peroxide, or otherwise 'contacted'with thesolution. The

period of contact between the aqueous hydrogen peroxide solution and thefoodstufi will depend, in general on the freshness of the material beingtreated. I prefer ordinarily to employ treatment periods of about tenminutes, although periods ranging from three minutes to thirty minuteshave been employed at various times with complete success.

It has been found that the concentration of the aqueous solution ofhydrogen peroxide utilized should preferably be 1.0% H20: or less.

Ordinarily I prefer to use concentrations of hydrogen peroxide rangingfrom 0.1% to 0.5%. The pH of the aqueous solution of hydrogen peroxidemay be adjusted within the range 3.0 to 5.0 by the addition of any acidor acidic material, although I have found that best results are securedwhen lactic acid is added to the aqueous utilized with specialadvantage, as by, the presence of the lactic acid not only are thefoodstuffs of animal origin preserved in the fresh state, but theirquality is favorably influenced by the action of the lactic acid.

It is possible to employ a mixture of acids or acidic materials, ifdesired. Frequently the aqueous solution of hydrogen'peroxide will alsocontain abuffering material, in order thatthe pH may be maintainedwithin the desired range, and as buffer salts I may add the variousbuffering agents known to the art such,-for example, as the alkali metalbisulfates, glycocoll, betain hydrochloride, the. alkali metalphosphates, or similar salts or compounds.

In carrying out my improved process for the preservation of foodstuffsof animal origin such 5 as meat, fish, etc.', wherein the animalproduct,

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such as fish, may be readily preserved without special difiiculty forperiods of four days, five days, or even longer, the foodstufi 'is firstcontacted with the aqueous solution of hydrogen peroxide having a pHwithin the range 3.0 to 5.0, this solution being prepared as previouslydescribed. Although immersion is generally the easiest way in which thefoodstuff may be contacted with the hydrogen peroxide solution, othermethods -of contact, such as spraying, may be adopted. Only a relativelyshort immersion period is necessary and, it is desirable following theimmersion, to pack the fish in ice containing hydrogen peroxide. Formost satisfactory results, therefore, I first immerse the foodstuif inthe aqueous solution of hydrogen peroxide for the short periodpreviously specified, and then pack the foodstufi in ice containinghydrogen peroxide. This treatment is found very valuable in the case ofall foodstuff of animal origin, and is especially valuable for thepreservation of fish.

ous solution of hydrogen peroxide having a pH within the range 3.0 to5.0, and then packing said foodstuffs in ice containing hydrogenperoxide.

2. A process for perserving fresh unfrozen foodstuifs of animal originwhich comprises subiecting said foodstuffs to the action of an aqueoussolution of hydrogen peroxide having a pH within the range 3.0 to 5.0for a period of time Fish so preserved were found to be extraordinarilyfresh and of excellent flavor, even after relatively long periods ofstorage.

It should be understood that the details of my invention which have beenpreviously given are to be regarded as illustrative and not restrictiveexcept insofar as necessitated by the appended claims. Since variouschanges and variations may be made in the invention as described withoutdeparting from the true scope or spirit of that invention, its scope isto be determined from the appended claims and prior art.

I claim:

1. A process for preserving fresh unfrozen foodstuffs of animal originwhich comprises subjecting said foodstuffs to the action of anaqueranging up to thirty minutes, and then packing said foodstuffs inice containing hydrogen peroxide, said ice containing hydrogen peroxidehaving a DH falling within the range 3.0 to 5.0.

3. A process for preserving fresh unfrozen foodstuffs of animal originwhich comprises treating said foodstuffs with an aqueous solution ofhydrogen peroxide containing lactic acid and having a pH falling withinthe range 3.0 to 5.0 for a period of time up to thirty minutes, and thenpacking said foodstuffs in ice containing hydrogen peroxide, saidhydrogen peroxide ice having a pH of 3.0 to 5.0.

4. A process for preserving fresh unfrozen foodstuffs of animal originwhich comprises treating said foodstuffs with an aqueous solution ofhydrogen peroxide containing lactic acid and having a pH within therange3.0 to 5.0 and then packing said foodstuffs in ice containing hydrogenperoxide, said hydrogen peroxide ice containing lactic acid and having apH within the range 3.0 to 5.0.

5. A process for preserving fresh fish in the unfrozen condition whichcomprises contacting said flsh with an aqueous solution of hydrogenperoxide having a pH falling within the range 3.0 to 5.0 and thenstoring said fish in contact with ice containing hydrogen peroxide.

RUDOLF THILENIUS.

